Airway traffic controlling system with verification of communicated messages



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N. D. PRESTON ET AL AIRWAY TRAFFIC CONTROLLING SYSTEM WITH VERIFICATION 0F COMMUNIGATED MESSAGES QUEUES@ mmmmmmmmw@ EUGENE@ DE D HHH E@ HHUUQ .O XML m XML XML,

Sept. 6, 1949.

Original Filed March 3l, 1944 INVENoRs NDPVGSTOn and FBHTohcoc-,K

. THEIR ATTORNEY N. D. PRESTON ET AL AIRWAY TRAFFIC CONTROLLING SYSTEM WITH ION` OF COMMUNICATED MESSAGES Sept. 6, 1949..

VERIFICAT Original Filed March 3l, 1944 2 Sheets-Sheet 2 nventors NDPreson and FBHchcock WMM Patented Sept. 6, 1949 AIRWAY TRAFFIC CONTROLLING SYSTEM WITH VERIFICATION OF COMMUNICATED MESSAGES Neil D. Preston and Forest B. Hitchcock, Rochester, N. Y., assignors to General Railway Signal Company, Rochester, N.

Original application March 31, 1944, Serial No. 528,926. Divided and this application October 17, 1946, Serial No. 703,764

12 Claims.

This invention relates to systems for controlling traffic on airways, and more particularly to an airway traffic control system for scheduling flights on airways with means for verifying the messages communicated between a control point and the flights travelling over the airways.

This application is a division of our prior apcation, Ser. No. 528,926, llled March 31, 1944, now U. S. Patent 2,439,862 granted April 20, 1948.

In connection with this invention, it is assumed that every plane operating on the regular airways (except at certain excluded low altitudes) will be required to have a suitable authorization or clearance from a traffic control center to ily at allocated altitudes between designated llXes at certain scheduled times, andl that the Vprogress of each flight will be shown by communicating with the control center in some suitable manner, the usual form of overtime report giving the identiflcation of such plane and its time and altitude as it arrives at or passes over each of the llxes in its route.

The primary object of this invention is to provide a system for facilitating and safeguarding the Scheduling of flights and the issuance of clearances, in order to permit prompt, accurate and complete advance planning of flight schedules so as to avoid congestion at terminals, and the like, and to maintain a suitable time or space separation between flights safety.

Considering generally the contemplated organization and plan of operation of the system embodying this invention, and without attempting to deilne the nature and scope of the invention, it is proposed to provide a flight progress board in the traffic control center on which electrically operable changeable indicators may be set by suitable manual and automatic control so as to display the desired data of flight identication, estimated time, altitude, direction and the like, for flight schedules which have been authorized by issuance of suitable clearances, the data of such scheduled flights, as it is posted on this flight progress board being kept up to date and changed to show the progress of each ilight by operating time indicators to display the overtime as reported for each x and also automatically wiping out the entire posting belonging to the flight in question for the next fix in the rear.

It is proposed to provide for use with such a flight progress board suitable manual or automatic control means for setting up and displaying, preferably in check display units associated in the interests of with the respective fix panels of the flight progress board, the data for a, proposed or tentative flight plan or schedule, including an estimated time of arrival of this flight at the established fixes in the proposed route as determined in a suitable manner by manual or automatic calculation. Before such tentative or proposed flight schedule is approved and posted on the flight progress board, the estimated time and altitude as proposed for each x in the route has to be visually or automatically `checked against the times and altitudes posted for all of the prior scheduled flights in such a manner as to detect any conflict in time and altitude Vat these fixes, and also-for each interval between such fixes, thereby determining that there is sulcient space or time Separation between the proposed ilight at all points of its route-and all prior scheduled ilights to prevent collisions if the authorized schedules are maintained.

When a proposed flight schedule has been set up, and checked in this manner for time and altitude conflict and is foundto be acceptable, such schedule is communicated to the pilot to constitute his authorization to fly at altitudes and times specified. While such schedule or clearance may be communicated to the pilot and verified in any ldesired manner, itis proposed to provide as part of this system automatic means for converting the data of the proposed ilight schedule, as approved, into a teletype code during the operation of posting this data on the flight progress board, andi for utilizing such code to transmit teletype messages over line facilities to any desired point for communication to the pilot by radio or the like,V and also to"operate a local printer for the purpose of making a printed record of each flight schedule.

The various features and general characteristics outlined above appertain to a, complete system such as'disclosed in the parent application, Ser. No. 528,926, mentioned above, while the features of this divisional application are more particularly directed to a portion of the complete organization and includes means for checking the communication of each approved flight plan or schedule to the pilot by having him report back to the control center by radio, telephone, or teletype facilities, the complete schedule as he has it before him, and by checking such schedule as reported by the pilot against the settings of the indicators on the flight progress 'board to detect any discrepancies due to errors in communication, to thereby verify that all of the altitudes and times for the xes in the schedule tobe used the different panels of aflight` progress board which may be set by an operator-as hereceivesI the schedule reported back to him by a pilot, which dials are connected., to suitable. l apparatus as to automatically check following.;the; actua: tion of a. suitable verification push button whether or not the reported message as thus set up conforms to the schedule for that flightas posted on the associated ight progress board. The organization providing this checking feature is so arranged as to utilize busses in commonfor the various panels and tddepend upon correspondi ence inx -position, org;indicatorsl andsetting dials inesuch awayasto reliably chekfthe positions of .the dials-asltheyareyset,

The` proposed?completeI system also includes provision. for revising or cancelling flight sched- 'i ules 1in. whole or in. partfasv Wellas srevising flight schedules up on ,tl' 1e' latest information sothat checking of afreportedfschedule;from a Apilotis checked'- against thelatest andl proper information..

Animportant ch aracteristicA of-v the*t system of this inventiomasfa wholefis-thatall of the parts and; circuits have,l been` specially arranged and organized; to` provide for; a lpositive l actuation of the.- changeableA indicators; andeV other. movable` 2&-

elements. vinJthc system inA response to, thel energization; oficircuits and/inf accordance withthe principle v 'off 'failure 'onthe sides ofi safety, so

that any..A bad .contact, broken. wire or other -circuit failure will be at: once,manifestedr:by an` Y abnormal; operatiQIl.: of: y:the systenih Other .attributes-Operating characteristics, and advantages of the isystemyoi this inventionwill be impart-apparent; andgirrp art pointed; out as the description; progresses.

Ins describingatheinvention, in detail; reference will` be made tothe accompanyingdrawings, in which vsimilar letter-reference characters are u sed.. to designate; similar, parts throughout the characters have beenymade; generally distinctive bic-the; use ,foil thedristinctivef preceding or suc.- ceeding numerals, and ing-which:

Fig- Lillustratesga flight, progress board organ'- izedin accordance'with the fpresent invention for displayingproposed and scheduled flight data ,by the setting: of Achangea-ble*indicators.;

Fig. 2 illustrates the apparatus;andl circuits employed fonvericatiomoa schedule, as repeated by. a pilot, with j-tlic :po stingsd that schedulegonthe .night progress' boardof- Fig. 1f; and

Fig. 3 .is 1a.rep etit iony of 5. themanually operable Contact dials illustrated-im g.y Zwandfgshown in this Fig. 3,so as to clearly indicate-,the relationships of such dials-withfthe differentgpanels of the ightprogressboand.

In order to.facilitataanunderstanding of the operation` ofrthesystem, and as a matter of convenience in i illustrating a, specific embodiment of the inventionin the Yaccornpanying draw-ings,4 the relays and-circuits particularly--relating tqdiffer.- ent.. functionsfcr stepsTx in.. the operation.v ofi the Systemfhave beeefshwri eearatelrby- `themselves in. the different gures; and1 the; association and -inter@onnectienfbetweenthese different4 groups :of

4 circuit drawings are indicated by diagrams and the use of like reference characters. Also, the relays, scanners, and Various other component devicesjof the systemihaye been illustrated in a A diagrammatic or conventional, manner in the drawings, the contacts of relays in some instances being shown at diierent places than the operating coils or windings. Likewise, arrows with the symbols (-l) 'or are used to indicate connectionato opposite terminals of a suitable battery or other" convenient source of operating current.

Inconnectionlwith the nomenclature used in the description system of this invention, it will be l noted that like letters will be employed to denote apparatus of. similar functions and that preceding numeralsin general Will designate the registration space of a fix panel with which such apparatus'isassociated while a following or succeeding numeral will designate the digit or element of thatspace; Also; forfacilitatingianunderstandingr ofi they systemt the lettersiA,y Bf andiC are respectively assignedgto threegsuccessiveiixes ofran airwaieV and,1 the use: of; these lettersv precedingvr a reference v`character.; denoteslthat'` the associated device belongst'o the-nxdesignatedbysuch preceding; letter. There'. are of zcourseI certain; exceptions to this generalorganization voffreference character .assignments `inorderv` to, maintain A, sim- Yplicityin the use-of reference"characters-'for such a complex system- General'orgam'zation ofthe system- Before-considering in; detail-the contemplated 1 operatiorn of-the4 system, and describingv typical examples of such operatiomit would appear' to be expedient to indicate some of the-more-signi-cant component -partsand Irl-alge vaebriefz survey of the generaly organization of `the @syste-m.

Flight prognfessl board- The flight progress boardfmayJ beesaidto -be-thefpredominantelement of the system and the one with whichzthe vother componentpartsare.operai', iv e1y l associated.l For the-purpose ofsmplifying the draw ings, thein- ,'Vention vhas .beenshownz applied to; a small DOIT- tion-or. sectorl ofA- one airway; comprising-radio xes or markers', conveniently identified by:v letters- VA,

B. andVv C.; but it shouldgbev, understood that the invention may, bei applied,-to any desired, number 1 `ol? and to Various-garrangementsofair-ways as will be discussed more in detail later.

Thegllighteprogressfgboardfcomprises a'fplurality oifix` panels, one foreach nm, andlEig@ 1v illustrates such ,panelsfor threexes A, B and .C1 .of the -siredy letter-nV or; guref.toi-represents,thelsignicant data for anightplannschedule. Asillustrated ther flightdata finI apostmgqspace comprises:

im-1. ight identication byfnumbers; ,or combination of letters and numbers, shown for two digits only; (b) estimated scheduled time at the fix in question provided by four indicators to give the time on a twenty-four hour clock basis; (c) the altitude allocated to the ilight at the x shown .by one indicator; (d) the direction of movement of the ight with respect to the arrangement of the fix panels shown by one indicator exhibiting an arrow symbol or equivalent; and (e) arrival or overtime at the x in question as reported by the pilot and indicated by two indicators in minutes and tens of minutes. It is to be understood that four digits of overtime be provided if desired.

The check display unit includes the same type of indicators, and for the same data groups except for overtime; and the indicators forA the flight number, and for the time and altitude are preferably arranged in the same vertical column with corresponding indicators in the schedule posting portion of the fix panel. The various vertical columns of indicators are identified by suitable markings on the panel.

Changeable indicators.-Various types of indicators may be used in the circuit organization constituting this invention, such as disclosed for example in the application of O. S. Field and S. N. Wight, Ser. No. 489,776, led June 5, 1943, now U. S. Patent 2,378,294 granted June 12, 1945, in which the indicating drum and position contacts of each unit are operated from a driven shaft by energization of an electromagnetic clutch. Another form of self-propelled indicator unit is illustrated and described in detail in the above referred to parent application, Ser. No. 528,926, and this indicating unitl comprises an indicator drum mounted to turn on a vertical axis supported in the lower frame member of the indicator unit. The numbers, letters or other desired symbols on the periphery of this drum are exhibited in its diierent positions through the opening in a suitable mask forming the face plate of the indicator unit. The indicator drum is connected by suitable gears to a self-propelled driving mechanism or operating element which is operated step by step to its diierent positions by an operating magnet or solenoid. Without describing the details of such an indicator unit it is suicient for the purposes of the present disclosure to know that the operating mechanism in moving step by step to its diierent positions not only moves the indicating drum, but also one or more groups of position contacts, so that for each indicating position of the changeable indicator one or more contacts will be closed for that position. In addition, there are contacts for certain positions which may be opened as well as closed, and such contacts for the normal position are lconveniently termed empty-full contacts opened or closed as the indicator is moved out of its blank position. The position contacts are preferably of the same type disclosed in the Field- Wight application, Ser. No. 489,776, above mentioned, comprising contact fingers arranged in the form of a barrel and supported by an insulated member and operated from the inside by a roller connected to the driving shaft operated by the driving mechanism. The empty-full contacts may also be supported on the same insulated member and operated by another roller on the same driving shaft.

The indicator units vfor the various rows or spaces of the panel are supported on a, suitable frame or mounting structure providing in eiect cells into which the indicator units may be inserted; and each indicator unit is preferably made quickly detachable as a whole for repair or replacement purposes by employing a plug coupler of suitable construction to connect the wires of the indicator units with the external busses and wires of the system.

This same general type of indicator unit is employed for the registration or posting spaces and for the ycheck display umts in the x panels 0f the iiight progress board. For the purposes of the present disclosure, each indicator structure is considered to have eleven positions as above described, with a display drum bearing the particular data which that indicator is to display. But it is a characteristic of all indicator display drums that they have a blank` normal position.

The iiight number display drums are provided with the numerals 0 to 9 in their operated positions, and this is also true of the unit minutes and unit hours schedule time, as Well as overtime unit minutes.

The display drums for the tens of minutes; schedule time and the over-time tens of minutes: have the numerals 0 to 5, while the tens of hours schedule time have only the numerals 0, 1 and 2.

In the case of the altitude display drums, the numerals 2 to 11 are used, and thus a single in dicator can display the levels or altitudes most Icommonly used for commercial transport purposes. But it is to be understood that two indicators can be used for each space of a posting panel to display the altitudes on the basis of units and tens, if a greater number of altitudes than ten is desired.

The direction indicator display drumseach have four arrows, two for one direction and two for the opposite direction; and for convenience in the disclosure, those arrows pointing to the right are assumed to be next adjacent the blank position in the direction of the rotation of the drums, while the arrows pointing to the left are assumed to be in the last two operated positions.

The flight controller board associated with the flight progress board as disclosed in the parent application has been omitted from this disclosure for the sake of simplicity in this divisional application. However, the ilight progress board has associated therewith, as indicated in Figs. 2 and 3, a control board for the monitoring operator upon which the time and altitude dials associated with each x panel are located, as well as thelight number dials and a verification push but ton VPB. It is proposed that these time dials be used by a separate monitoring operator in a way which will leave the ilight controller or operator free to continue with the advance planning of other iiights while this procedure of clearance verication is in progress. The time dials of Fig. 2 and the master ilight number dials with their associated veriiication push-button VPB have been shown on the monitoring panel in Fig. 3 to illustrate the same physical association illustrated in Fig. 2. The organization of positioning contacts and setting dials diagrammatically shown in Fig. 2 are for enabling the times and altitudes for the various xes, as repeated by a pilot from his received schedule, to be varied with the flight schedule as posted on the flight progress board and used as a basis for conilict detection described in the parent application.

Verilcatz'on of cZearances.-It is highly important that a pilots understanding and record of the flight plan or clearance which constitutes his authority for operation of the plane at the altitudes and times specified over the different fixes ofi. an. airway, should .conformwithfthegtimeseand altitudesv posted in the correspondngi; X: 1panels on the flight progress board-,- because zitgisrthese postings again-st; which-x newly proposed flight plans must be, checked to deter-minevwhether Qr not they are in conflict with theI flights; already having clearances. Thev communicationof, the clearances by voice `or code over linerwiresor by radio from the flight contlollentoytheepilot is necessarily open to-mistakes andito, check against such errorsin the communication of'such clearances, it VisyproposedthattheA g-ht; data transmitted to thepilot shall be yrelayed back; to the central oillcev in, a suitable manner sottfhat it;.may be checkedffor identity with, postings on the Yflight progress board.. Ifl thetimes and, alti,- tudes. as. relayed back exactlycorrespond with those` posted, then it is certain; that-thepilots authority corresponds with the flight; progress board, except for the extremely remote circumstance that errors of exactly compensatingcharacter are made in thev chain of communication fromthe central ofcetothe pilot andback.

In; View of the above considerations, itispr posed that anT organization be provided f-.or clear,- anceverication. It is further proposedethat the apparatus and circuits provided for clearance verification will beso organizedV with lrespect-.to the-other functions of theposting system. that .it can function without interference therewith; and infact cany bevused bya sepa-rate monitoringA op,.- erator in a way which Will leayetheight-controller or operator tree to continue withitheiad.- vance planning of other flights while this` procedure of clearance verification.' is ini progress.v

Fig. 2 illustrates a simplified organizationfol suchV clearance verification, it being assumed that the other functions of thesystemremainas previously described, and as morefullyI disclosed in the parent application, Ser. Nol'528,926..y This organization for verification, asyshowncior-purposes of this disclosure, employs aseparate set of position contacts on the-flight numbeljschedule time,-andf altitude posting indicators. For-coniveniencein the drawing, only twoflightn-umber indicators, two scheduledtime indicatorsand one altitude` indicator have their setof Contacts shown in Fig. 2. The various.positionsyofnthe schedule andy altitude sets-'ofrcontactszfon as; X panel are connected by buses` whchrextend to their respective set of dials for timevagndi4 altitude for that fix. The variousfpositions-ofthe `flight number sets of contacts for allix panels-:arecon,h nected,v by buses for corresponding digitsasingle-set of flight number -dialsone-dialirf.or\ each digit. Also, each posting spaoefisfproyided with a.. correspondence relay, for each digit lofthe flight number, such as relays I CQR In and I-COR-2 for.. space I of panel A, forexample.

It is lcontemplated that theflight, numberto.- getherZ with the timeand altitudeffon eachlx, in the-flight plan or clearance; asreported by;` the pilot, will be manually` set ,upI by the-monitoring yoperator on suitable dials inthe central office-and then. a verification.y button VPB will: be actuated; The actuationY of this verification buttonVPB applies negative energy to 1 thev partculan--bus -selectedby the flight numbervdial, VFN-Iffpr-athe rst digit to energize` thecorrespondencerrelay; such asrelay I.-.COR-Ii or:,2'C,ORf-.I[ for; that particular posting( space-ofeachfpanelthaying a corresponding nightnumber posteda therein, prouidingno'fover-time hasbeem reportedi and;A posted inthe corresponding space.l Eon exampleiassumfingthat theindicators for space Zgcf panel A are vin;positions l and; U withA the flight. number setting dials VFN-Ij and VFN--Zf in; corresponding positions, a circuit isclosedfiorf relay 2;-COR--I from (-l-:J-through a circuitincludin-g empty-full contact 385 of; an over-time indicator: for space 2,; in an empty position, windings of. relay 2,-.-COR-I, contact arm of theiindicator. for the first-` digit of ilight number iiiposition I-, panel bus 386, master ybus 381, flight; number dial VFN-I in position I, operatedl con-tact, 38,8 of veriiication button VPB, to Energization of; the correspondence-relay' Z-CGR-I closes a front contact 389 to complete the;energizationy of the correspondence relay 2-COR--2 providing the number set up on the ilight number dial VPN-2 for the second digit of flight number energizes a bus corresponding to the position. of the indicator for space 2- in the second'` digitV of the flight number. For example, assuming cor= respondence exists between the secondldigit flight number indicator of space 24 of; panel` A and flight numberdial VFN-2, a circuit isclosed'for correspondence relay- 2-COR-2 from C+), through front contact 389; ofv relay 2-COR--I, windings of relay Z-COR-Z, contacts of flight number indicator for thesecond digit in position El, panel bus 393, master b usBBI; flight number dial VPN- 2 in position Il', contact 3 92 of buttonv V'PB in an actuated position, to

The picking up oi the correspondencerelay for the second digitY of a. flightv number causes positive energy (-i-) to be applied tothe position contact arms of the schedule time and altitude indicators for the corresponding space, as Well as completing a circuit to a, busforenergizing a flight correspondence relay, such as relay A-FC., for the corresponding panel. A similar relay, such as relay A-FC, is pickedy up for each fix panel, inwhich a, posting` has' been made for that flight number. More specifically, if the flight has postings at fix panels A and B, the relays A-FC and B-FC, are both. picked up, and assuming that a conditionl of correspondence exists at both fix panels, az'circuitI is closed for the master verication relay CVR from (-1-), through a circuit including front contact 4110; of relay A-FC and front contact d I of relay B---FC` in multiple (through the selections of any other panels indicated by small. cc); front contact 402 of 'relay RAV for panel B, frontcontact 403.01? relay 'TV- 2 for panel B, front contactd of relay TV-I forpanel B, wire 405, front contact 40B of relay RAV for panel A, front contact 401 ofv relay TV-2 for panell A, fronticontact 408 of-'relay TV-I, for panelv A, vwindings of' relays CVR, tol

It is noted that this circuit just pointed. out for the master verification relay., CVR is closed dependent upon. the picked-'up condition of l the relays |IVI, 'TV- 2 and RAV for both panels A. andy-B, and thus indicates that correspondence exists between the scheduled' time andrthe` reportedy time as well as-between the scheduled altitude` andthe reportedY altitude. More specically;thesecorrespondence relays are energized when correspondence exists becauselthe picking up ofthe correspondence relay for. a posting space of. a. panel, such asrelay Z-COR-,Zapplies energy through front contacts. 395,y 396,L 391 vto lthe contact: armsof. the scheduled time-and` altitude indicator units for the corresponding'space. Thisenergizesthe panel buses to.complete circuits, forfthe relaysTV--L TV'2 :andRAVf for that. fix panel if thetimesandi-a1titudes.-re ported as. set up. on. dialsRT-FI ,f RTL-2 and'lti correspond with those posted for the particular fix panel in question.

If the times and altitudes, as reported, correspond at each fix panel with those posted for that panel, resulting in the energization of the master clearance verification relay CVR, the lamp 4l I is illuminated by reason of energy flowing through front contact H2 of relay CVR, thus indicating to the monitoring operator that a final approval may be given to the pilot to proceed upon the clearance information previously transmitted. If on the other hand, the time or altitude, as reported for a fix, does not match the postings, or if no time or altitude is reported for some X panel where there is a posting, then the circuit for the master clearance verification relay CVR is incomplete and an indicating lamp is lighted to show which panel is involved.

More specifically, if there is a posting in panel` A causing the relay A--FC to be picked up opening back contact 409, but because of a lack in correspondence in either time or altitude and one of the contacts 406, 401 or 408 is open, then a shunting circuit including resistor M3 and lamp 4|4 allows current to flow and light the lamp M4. This circuit including lamp M4 allows the flow of sufficient current to illuminate the lamp to indicate that there is a lack of correspondence between the reported schedule and the posted schedule at this panel, but such current flow is insufficient for the energization of the master verification relay CVR. In this way, there is a check provided upon the pilots understanding and record of his flight schedule since the failure to receive reported information with regard to a fix included in the schedule as posted on the progress board causes the verification apparatus to bring this to the attention of the monitoring operator. Under such circumstances the monitoring operator will not give his final approval of the schedule to the pilot, but will recommunicate with the pilot and determine the reason for the lack of correspondence.

It should be noted that each of the relays A-FC, B-FC have the multiple contacts such as 409 and 4|0 respectively for determining when the selections for their respective panels are to be included in the circuit for the master verification relay CVR. Also, it will be seen that each of these relays has contacts, such as contacts 400 and 401, for activating this circuit regardless of the point in the airway at which the schedule for a flight begins.

Since a clearance verification may be required while a flight is in the air and after it has passed one or more fixes and duly reported its overtimes, and since the time and altitude for such ix or xes passed by the flight would not be included in the report of the pilot as a part of his revised clearance, an empty-full contact on an over-time indicator (such as contact 385) is employed to avoid the energization of the correspondence relays for such space where overtimes have been reported, and thereby prevent the energization of a relay, such as relay A-FC`, for those panels where the overtimes have been posted.

In order to facilitate the disclosure of this rather complex organization in the parent application, various component parts and features were segregated into groups of drawings for simplifying the description of the features relating to such component parts; and it is one of these groups of component parts and features which comprise the present divisional application, but it is to be understood that the complete system of airway traic control of the present invention contemplates the composite use of all of the features disclosed in the parent application. On the other hand, the features and component parts of the inventiondisclosed in this divisional. application may be Vused in various combinations, and certain features of the complete system may be omitted without detracting from the utility of the Various other portions of the system.

Havingthus described one form of an airway trailic control system and certain auxiliary subcombinations thereof, as one specific embodiment of the present invention, it is to be understood that various modications', adaptations, and alterations may be applied to meet the requirements of practice without in any manner departing from the spirit or scopeofthe invention eX- cept a-s limited by the appended claims.

What we claim is:

l. In an airways traic control system, the combination with a flight progress board having rows of changeable indicators for posting flight data, each of said indicators including position contacts selectively closed in the different indicating positions of that indicator, a set of buses for each group of like indicators in the several rows, circuit controlling means for selectively energizing said sets of buses in accordance with the data for a flight schedule as reported by a pilot, circuit means for rendering effective the position contacts for-the changeable indicators for any selected row' only one row at a time, and means responsive to the energization of said circuits including a singlecorrespondence relay for each Vof said sets of buses and effective only ifall of the data reported by the pilot as set up by said circuit controlling means conforms with the position of the indicatorsof the flight progress board then rendered effective. 4

2. In an airways traflic control system of the character described, a number of X panels one for each established flx of an airways layout, each vof said flx panels comprising rows of changeable indicators for posting data for flight schedules including an identifying flight number, time and altitude; sets of panel vbuses for the corresponding indicators in the different rows of each panel; setting means for selectively energizing said buses for designated fixes in accordance with the flight schedule reported by the pilot for a given flight, means for each panel operated automatically only when a posting in that panel agrees with the flight data reported by the pilot and set up by said, setting means for the corresponding fix, and means for indicating if the postings for the given flight conform with the data reported .by the pilot for all of the fixes designated.

3. In an airways traffic control system, a plurality of nx panels each having a number of rows of changeable indicators for posting flight data including an identifying flight number, means for Ioperating said indicators in said panels to post data for scheduled flights at each nx involved and including a reported overtime at that x, vsetting means for setting up a given flight number and the data vfor the corresponding flight as reported by a pilot, relay means for automatically designating each of the panels having therein a posting for the same flight number as setup by said setting means only providing there is no overtime data posted in that panelfor such flight number, and means .3lincluding said relay means for verifying the flight dataasfreporte'd bythe-pilot 'withthe postings in saidpanels.

`4..In an airwaystrafic control system, a x panel lhaving .a number f registration `spaces each including a plurality of. indicators 'for posting identifying flight `nu`rnbe1s,f.tim`ey andA altitude; a set ofbuses for eahgroup-f like indicators in several spaces', each ofsaid'indicators including position contacts '-for, seletively v establishing circuit connections 'tothe' corresponding vset of buses inaccordance with the indicating1p`osition of that indicator, .means for .selectively 'jener-gizing thebuses otsaid sets forilightlnurnber identification, and..m'eansY .associated v'with each space and ,including l.said .position .contacts for selectively energizingthe,setsofbuses 4for time and altitude in .accordance with the .position of the time vand altitude indicators .for la -space onlyif the position of the .flight number 'indicators in that space correspond with"'.th e flight number buses then energized, .whereby thetime and altitude buses vmay 'be .energized "to .conform with any posting lin the panel `-selected rby`iglit number identity.

5. 'In an airwaysrtr'aflic Acontrol system, incombination with a j'flight,-prlogress board .comprising a plurality f lix.panls' .eahincludinga number of rows .of changeable .indicators .for Aposting the data of night .shedules Fmeansffor .posting a flight Vschedule including van .identifying Yflight number .in .some :row `of each X 4panel involved, whereby .a plurality of .rows tof teach .x rpanel may at times havethedalta-forafnumberof different flight .schedules ,posted at 'that vtime,set tingmeans selectively closing contactslinzaccordance with vthe Adata .of fanly flight schedule reported by apilotfand including the flight number identifying that ight, :automatic means 'for picking .out the rows of ichangeable .indicators in each fix panelhaving-datapostedtherein relating to the .flightgnumber then yset up-.by'said setting means, and ,means foroheclsing the correspondencelbetween the eflight ,data for the identil-led .flight as `posted 7in the -changeable indicators .with :the ,positions of the contacts 'of said setting means. I

6. In an .airways -trairlc control system, the combination with a .flight progress Aboard with diierent nx panels each ihavingvrows sof changeable indicators foripostingithe ilightrda-ta =.0fdif ferent scheduled nights, each arow .including in- -dicators operableto positions to indicate 'the identity of the vflightto which (the `data '-of that row relates, .flight vschedule setting vmeans -manually .operable V4to diie'rentlpositions in accordance with the flightdata of ascheduled flight as reported by la A`pilot and. including setting means operable to positions to identify the reported flight, automatic means governed-bysaid setting means for .locating `by flight videntification the different rows o'fjsaid ,panels cluding data relatingl to `the-.sclzieduled nflight then identified 2by said setting means, and means including buses 'and correspondence rel'aysm'for giving a distinctive indication when the iiighft data `setting means is in positions correspond-ing to the positions ofthe di'ffr'erit `indicators of the x` panelsV relating to the latal of the'lidentiied flight.

7. In an airways tr'ac control system, a flight progress board'haviK-r'g' ,fix .panels *for posting the dileren't flight vschedules for the various fixes over which the Vflights may passa reporting board having manually operable setting 'dials movable topositionsior each-flight schedule reported by a pilot, and means for -automatically verifying correspondence I between the data -in the several fix panels of the'ightprogress board with the data of said setting-dials, and means for illuminating an indicator for each x panel with which correspondence fails to exist.V

:8. 'In-an airways traiiic control system, apluralityof fix panels each having a-number of rows of changeableindicators for posting flight identifying members and accompanying flight data of a flight schedule,a master circuit controller associated with said fixpanels, each-of said indicators including positioncontacts for selectively establishing circuit connections -in accordance with the indicating vpositions of 1that indicator, individual set of time and altitude circuit controllers associated with-each 'fix panel, circuit meansincluding correspondence 'relays associated with each row Vof eachxpanel cooperating with-said master-circuit controller-and the position contacts of the indicators displaying flight identifyingnumbers tceselect therowof each fixpanel relating tore, givenfflight schedule, circuitmeans including panel correspondence relays associated with each `xpanel for indicating-when saidindividual circuit controllers and the indicators -for the selected-row of ythatfnx ypanel are in corresponding positions, and circuit `means including contactsfof said panelvcorrespondence'relays and closed vto energizing Aa -master -indication relay only if the panel correspondence relaysof each fix `panel -are in energized conditions, said correspondence .relays `being required to bein energized-conditions for only 'those xfix rpanels 'having indicators displaying -a flight identifying num-ber corresponding tothe one set upon said master circuit controller.

:9. `In `an airways -traiTic--control system, -the combination `with -a-flig-ht progress board having rows of changeable indicators including indicators for posting -ight identity and night data, each of said indicators including-position contacts selectively closed in the different indicating lpositions of that indicator, -a set of busses for each .group of changeable indicators in the several rows, circuit `controlling rmeans for 'selectively energizing said sets 'of busses in vaccordance with the Vight'schedule as reported by a pilot including flight identity Yand ight data, frelay means associated -with yeach lrow -and adapted to be energized when the flight identity se't up in accordance with the reported schedule causes the selective energization of said busses relating -to the flight identity corresponding with the flight identityset supon certain of the position contacts for 'that row, circuit means con-- trolled by the relay Ymeans associated with each row for rendering effective 'the position contacts for the indicators of vthat row displaying flight data, vand means responsive to the energization of lsaid sets of busses relating to Iflight vdata only if Ythe position contacts for the flight data indicators of the row then rendered effec-tive by the energization of said relay Ameans have posi'- tions corresponding to the d-a-ta reported by the pilot, whereby the ight identity of a sch'edule selects the vflight data -for that flight schedule so that it may .be `con-ipared with the flight data reported by the pilot.

10. lIn an airways traffic control system, a plurality of iix panels eachrhaving a number of rowsdof changeable indicators for posting flight identity, time and altitude, a set of busses for each group of like indicators in eachiix panel,

each of said indicators including position contacts for selectively establishing circuit connections to the corresponding set of busses in accordance with the indicating positions of that indicator, circuit mean-s for selectively energizing the corresponding busses of each set relating to flight identifying numbers in all fix panels, correspondence relay means associated with each row of each x panel responsive to the energization of the busses relating to flight identifying numbers if the position contacts of the indicators for the flight numbers in that row are in positions corresponding to the selective energization of said busses, said relay means acting when energized to render effective the position contact-s for time and altitude indicators for that row, setting contacts associated with each fix panel operable to positions to correspond to the reported time and altitude for that fix for energizing the corresponding busses of each set associated with that fix panel, other relay means associated with each x and relating to time and altitude for that X and energized if the setting contacts are in positions corresponding to the indicator position contacts then rendered effective for that fix, and circuit means closed only if said other relay means is energized for each x having some correspondence relay means energized for that fix.

11. In an airways traffic control system, the combination with a flight progress board having rows of changeable indicators including indicators for posting ight identity and related flight data, each of said indicators including position contacts selectively closing contacts in the different indicating positions of that indicator, a set of busses for each group of changeable indicators in the several rows of a fix panel, circuit controlling means for selectively energizing said sets of busses in accordance with the flight schedule as reported by a pilot including flight identity and accompanying flight data, relay means associated with each row and adapted to be energized when said circuit controlling means selectively energizes busses in accordance with Hight identity corresponding with the position contacts associated with that row of indicators, circuit means controlled by said relay means associated with each row when energized for rendering eifective the position contacts of the remaining indicators of that row, circuit means for preventing the energization of said relay means for any row when the posted flight data of that row includes an over time posting, and means responsive to the energization of said sets of busses relating to flight data only if the position contacts for the flight data indicators of the row then rendered effective are in positions corresponding to the energized busses of their respective sets, said means being required to be energized to indicate correspondence between the postings and reported flight schedules by the illumination of a lamp only providing a relay means for some row is energized.

l2. In an airways traffic control system, a flight progress board including a plurality of fix panels, each having a number of rows of changeable indicators for posting flight identifying numbers and accompanying flight data of a flight schedule, each of said indicators including positioned contacts for -selectively closing circuit connections dependent upon the indicating positions of that indicator, master circuit controllers associated with said fix panels, time and altitude circuit controllers individually associated with each fix panel, circuit means including correspondence relays associated with each row of each x panel cooperating with said master circuit controller and the positioned contacts of the indicators displaying flight identifying numbers to select the row of each x panel relating to a given flight schedule, circuit means including panel correspondence relays associated with each fix panel for indicating when said individual circuit controllers and the indicators for the selected row of that x panel are in corresponding positions, a master indicating relay, an energized circuit including contacts of said panel correspondence relays for energizing said master indication relay when the correspondence relays are energized for each fix panel having indicators displaying a flight identifying number corresponding to the one set up on said master circuit controller, and an indicator lamp controlled by said master indication relay.

NEIL D. PRESTON. FOREST B. HITCHCOCK.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,074,392 Herbst Mar. 23, 193'? 2,134,118 Foss Oct. 25, 1938 2,191,234 Hicks Feb. 20, 1940 2,264,563 Bumstead Dec. 2, 1941 2,386,743 May Oct. 9, 1945 

